Method of treating cereal grains



Patented Feb. l, 1944 UNITED- srATl-:slPirnaNT OFFICE METHOD F TREATINGCEREAL GRAIN S Theodore Earle, Pacific Palisades. Calif., assignor to Continental Baking Company, Wilmington, Del., a corporation of Delaware l Application April 15, 41940, Serial No. 329,725

(ci. :i3-28) 4 Claims.

This invention relates tothe treatment and surface-conditioning of cereal grains and more particularly to the detachment and removal from husked grains of the outer bran coat lamination normally forming the exterior surface of such grains, and has as an` object to provide an imeral; and particularly in the case of rice, oats, rye and Wheat, woody in character and entirely uniit for use as food, while certain of the inner bran coat laminations are characterized by valuable food properties.

In preparing cereal grains for -use as food it is often desirable to detach and remove one or all grains for food purposes with a minimum extrac-v tion from the grain of the fats, vitamins, and likedesirable constituents.

A further object of the invention is to provide an improved conditioning treatment for cereal grains which is susceptible of practice through readily-available equipment, which is rapid and emcient in operation, which is economical in use.

productive of vdesirable conservation'of the grain material, and which is readily adaptable to meet the requirements developed as an incident of the treatment and conditioning of specific grains.

My invention consists in the nature, specific character, sequence, and arrangement of operative steps as hereinafter set forth, pointed out in the appended claims and diagrammatically illustrated in the accompanying'drawing, in which- Figure 1 is avertical section through conventional -apparatussuitable for practice of the improved method.

Figure 2 is a iiow-sheet or diagram illustrating the sequence and nature of the successive steps comprising the improved method.

The cereal grains commonly used for food purposes are in general alike in that the grain berries, after removal of husks, consist of a starchy endosperm wherein is embedded a germ, and an of the bran coats, more especially the outer woody brancoat lamination, prior to milling or other treatment of the grain berry, and the methods conventionally employed for total bran coat removal have marked disadvantage in that too great va proportion of the grain berry suitable for lfood and containing certain desirable food elements is removed, it being customary'to remove the entire bran'coat, the germ of the berry, and a percentage of the endosperm in. order to insure complete removal of the undesirable bran coat material, the loss of grain material through such conventional practice frequentlv amounting to from twelve per cent to twenty per cent ofthe original grain weight. Additionally, conventional proc'- esses fail to permit of separatory deiinition between the outer'undesirable bran coat lamination and the inner lamination desirable for food purposes,- the entire bran coat normally being ground or rubbed oi as a unit; The improved method permits of detachment and removal of bran coat -laminations progressively and without disturbing the underlying bran coats, endosperm and germ vof the berry,thus effecting a marked saving'in grain material as well as preserving the food properties heretofore extracted, removal of the undesirable outer bran coat lamination being effected by the improved method with a weight loss of less than two per cent of the original grain weight'.

The improved method consists of three distinct phasesY vor steps, irrespective of the particular cereal grain being treated, which phases or steps may, in certain cases, be given eiect successively in point of time in a single apparatus unit. 'Ille three essential phases or steps of the improved method are-mst, a conditioning of the grain berries to loosen and initiate detachment of the t outer bran coat lamination; second, detachment envelope or bran coat surrounding and enclosing the endosperm and germ. The bran coat may consist ci a. single layer of relatively horny material. as in the Vcase of corn, or may consist of a plurality of separate laminations 4varying in number and specific character with diilerent grains. husked rice and wheat having bran coats consisting of six distinct laminations. The outer lamination 'of the bran coat material is, in genand removal of the 'loosened outer bran coat lamination from the grain berry; third, separation of the detached bran coat material from the cleaned berries. The ilrst phase o r step of the improved method is best accomplished by sustained agitation of the grain material in a bath of suitable liquid. such as water, through a time periodsumcient to permit the liquid to soak into. soften and wrinany speciilc form, y Aarrangement suitable to accomplish .the desired kle the outer bran coat and thereby loosen ,said bran coat 'from the underlying berry or bran coat laminations. Best results arehad in point of time and uniform conditioning when the gra-in material is immersed in a volume of liquid s uflcient to permit free suspension and circulation of the individual grainberries therethrough, and

when the liquid bath'and its contents is so agitated, by any suitable or convenient means, as tov maintain the grain berries in freely circulating suspension. As will be apparent, various forms and constructions of agitating apparatus suitable to the purpose above described are conveniently available, and it is immaterial to this phase of the method whether the agitation be accomplished by stirrers, impellers, paddles, air or gas jets, or otherwise, so long as the degree of agita,-

tion is suflicient to maintain the grain material in freely-circulating suspension in its liquid bath without'such violence as would result in breaking or shattering of the grain material.

The second phase of the improved method commined that an eilicient detachment of the char-V acter sought can be obtained by covering the interior surfaces of agitating apparatus with a coating of material, such as rubber, having a degree of yieldability such as to recess slightly when a' grain berry impinges thereagainst., To avoid' damage to the grain berries and to obtain a complete removal of outer bran coat laminations with maximum eillciency, all lof the surfaces exposed to contact with the grain berries should be cov-- ered alike with the non-abrasivematerial. The

faces-is a very moderate rubbing, the inertia of the grain berry deriving from its circulatory' action of the resilient material on the grain surmethod in the same apparatus. since said method phases alike involve agitation of the grain berries in a body cf liquid and naturally follow each other in a. closely-related time sequence. It is to be noted that the rubbing action depended upon in the improved method for detachment and removal of the outer bran coat lamination differs from the action had in mills and grindingl machines, even when rubber-lined. in that no pressure is exerted against the grain berries other than the very slight pressure deriving from the velocity and inertia of the grainberries moving in and with the agitated liquid.

'Ihe third phase of the improved method irlvolves separation of the detached material from thecleaned grain berries, and may be accomplished in any one of various specic manners, the 'convenience and practicability of the specific separation step to be employed depending, in many cases, on the character of the grain material and the manner in which the outer bran coat lamination detaches fromthe grain berries.` With wheat and rye, for example, the outer bran i coat-lamination separates from the grain berry in relatively large, thin, flake-like particles, which Y particles rapidly congest the agitating apparatus, slow down the grain berry circulation therein, and decrease the efciency ofthe detachmentl phase unless'promptly removed. In such a case, it is desirable and entirely practical to levitate the detached material away from the grain berries as such detachment occurs, and this may be accomplished by means of froth notation, use of air or gas jets, upward currents through the liquid body, and the like, all of which is within the present knowledge and teaching of the related art. However, with cer-tain grains, notably brown rice and husked oats, the outer bran coat lamination detaches from the grain berries, when treated as above describedin relatively minute particles,

. in the detachment phase has been accomplished velocity acting to brush the berry into and acrossv the yieldablesurface for a progressive peeling of the loosened bran coatl lamination, the nature' of relatively soft rubber being such as to facilitate this action in that the bran coat tends to stick or adhere slightly to the rubber surface during the momentary contact `of the grain berry with such surface. While rubberis mentioned as a material suitable incertain of its forms for lining of the apparatus wherein detachment of Y the outer bran coat lamination is had, it is to be understood that the reference to rubber is in no sense limitative, but rather typical of any and .all suitable materials 4having the characteristics essential to= the function for which the rubber is used in this method.- Material having the properties above set forth as essential to succsful practice of theimproved-method may bel approximately dened as adherescen-t.

As will be apparent, the apparatus wherein detachment of the bran coat lamination is eilectedrmay'be of construction, and operative circulation of the grain berries in the manner and for the purpose above'set forthf and lin'manyY to the inch will serve to pass the bran coat particles with a minimum and unimportant loss of cracked and broken grain material, the exact mesh of the screen being for a given grain.

'After 'detachment and separation of the woody bran coat lamination from the grain berries, the cleaned berries may be further treated as may be deemed expedient or desirable to condition the grain material for milling or other preparation as afood product. The remaining bran coat readily determinable 'laminations may be detached and removed from operations it will prove feasible and convenient to accomplish the first two phases ofthe inilavrovedY the berries, either by further' practice of the im-V proved method or through conventional process and apparatus, the under bran coats carrying suf-l ilcient desirable food properties to warrant their salvage andJ processing separate from theouter 2,340,313 beA dried by circulating air currents, application tive arrangement of apparatus may be employed.

Figure 1 of the drawing illustrates a conventional froth flotation unit of a type conveniently available and suitable for practice of the conditioning,

detaching, and separating steps of the improved method, this view of the drawing showing, in op. erative combination, an agitating chamber I adapted to contain water for agitation by means of an impeller Il suitably actuated by means of driving mechanism i2, and means I3 for removing the developed froth and material associated therewith from the upper end of the chamber I0;

all surfaces of the apparatus in contact with the water body and grain material fed thereinto being covered by a suitable`layer I4 of rubber or equivalent material. The graincleanedby the improved method has not been subjected to-heat or friction, retains the germs and such of the bran coat laminations as may be desired in the nished food product, presents a minimum of cracked and broken grains, is free from dust, and has lost but a relatively small proportion` of its original weight through the removal of the woody bran coat lamination. Because of the simplicity and rapidity of the improved method,v grain niateriai maybe expeditiously treated thereby at separation of the bran from the cleaned rice berries, the cleaned grain being then centrifuged for removal of excess water and finally dried by means of warm air. In this test the bran coat loss amounted to one ounce for every ten pounds of original grain, and the breakage of grains was less than ten per cent and none ofthe germs are removed from the grains. The cleaned grain berries were of good ilavor and highly palatable when prepared as food, and evidenced none of the characteristic disagreeable flavor imparted by the outer bran coat lamination. A comparative test, using a similar quantity of brown rice and a greater quantity of water, was run through apparatus wherein the surfaces exposed to contact with the grain berries were uncovered and all of metal. -In the comparative test the berries were rapidly ground'down to the starchy endosperm without any possible distinctive separation between bran coat laminations, and the damage to the grain material through cracking and breaking was so great as to render the method impractical. Fully 20% of the grains was so iine it passed through the 30 mesh screen with the bran.

- tice of the improved method from anything reremarkably low cost per unit of weight or volume,

and the nicety of control over the detachment phase made possible through the improved methd od is of material advantage in regulating the character and quantity ofthebran coat material retained in or on the nished lfood product.

-Figure 2 of the drawing illustrates graphically the sequence of steps to whichthe grain material is subjected in carrying through the improved method, irrespective of the character and combination of apparatus employedfor such purpose. As will beA apparent, .the rst four steps of the method as set forth in the diagram may be ace' .lamination while retaining they other bran coat material on or in available association with the grain berries.

As an example of the practical operation ofthe improved method, fifteen poundsof brown rice was charged into fiftypounds o! water contained sulting from comparable methodsvwherein such lining characteristic is absent, and that vpractice of the improved method is productive of new, ad-

vantageous, and hitherto unknown results in thev cleaning of grain. Y

Similarly, ten pounds of a hard, red wheat was agitated with iifty pounds of water in the rubberlinedapparatus above set forth with an impeller peripheral speed of approximately eighteen hundred feet per minute for about eight minutes. This `impleller speed was adequate to maintain thel grain in circulation and suspension within the liquid body. The bran coat material loosened and detached as a result of the agitation was decanted awa fro the clean berries and amounted to but per cent, by weight, of the original grain material, there being no apparent loss of endosperm or germ and practically 'no berry breakage in this application of the im.

proved method. 4The comparative test operated j without the use of the rubber lining material resulted in a detachment and separate removal of outer bran coat material substantially the same in amount as was obtained when the rubber lin-v `ing was used, but without the rubber lining therel the rubber lining eiects a two and one-half per cent saving of desirable grain berry material as well as insuring production of -a more desirable productthrough the elimination of breakage and u damage to the grain berries.

. Analogous comparative tests of the method in'a rubber-lined dotation cell equipped lwith a rubber-covered impeller and havinga capacity of sixty pounds of water. The cell charge was agitated through actuation of the impeller ata peripheral speed oi from fourteen hundred to sixteen hundred 'feet per minute for approximately five minutes, whereafter the entire cell contents was' discharged over a thirty mesh screen for .the rubber lining.

. Husked oats, or oat greats, comparatively treated in the identical manner described for the wheat, showed a bran loss of one and threes tenths per cent, by weight, both with and without the rubberJ lining. and a lloss orberry material amounting to less than Aone per cent when the .rubber lining was used and seven per cent when the test was operated without the rubber lining.

All of these tests clearly `show the practimlV 'advantage obtainable through the use of rubber lining and a further advantage in the character and quality of the cleaned berry product wherein `breakage and damage has been minimized by the use of the resiliently-yieldable material in rubbing contact with the grain berries.

While the improved method has been described in connect-ion with its primary function of removing exterior bran coat laminations from grain berries, it should be obvious that the method is conveniently susceptible of application to the cleaning of grain berry surfaces prior to and sep.- arately from removal of the outer bran coat laminations, since by reducing the time of agitation in the rubber-lined apparatus sufficiently to avoid loosening and detachment of the Woody bran coat, the grain berries may be adequately surface-rubbed vand cleaned by circulation past and againstthe yieldable surfaces of the apparatus lining- Since many changes in the specific form and construction of apparatus employed and in the specific relationship, duration, character, and sequence of process steps, may be had without departing from the spirit of my invention, I Wish to be understood as being limited solely by the scope of the appended claims, rather than .by any details of the foregoing description.

I claim as my invention:

1. The method of stripping non-nutritive, ex-

terior bran coat laminations from cereal grains for the productionv of peeled grain berries retaining their nutritive bran coat laminations and germ elements in substantially undisturbed, natural relationship, which consists of agitating and freely circulating the grain berries in water to terior bran coat laminations from cereal grains without materially disturbing the underlying, mi-

tritive bran coat laminations and the berry germ,

which consists of agitating and freely-circulating the grain berries in water to soften and initially loosen their exteriqir' bran coat laminations, non- `aurasively peeling time umri-linterna material from the berries through repetitious impingement of said berries, under the sole influence of' l circulatory velocities deriving from agitation of the grain material in and through a body of water, against, along, and into slightly indenting relation with resilient, adherescent surfaces,

l whereby said surfaces act to frictionally engage relatively large areas of the loosened berry coat material with velocity-retarding effect thereon and consequent sloughing of the engaged outer coat material from its berry, and separating the detached material from the peeled berries.

3. 'I'he method of stripping non-nutritive, exterior bran coat material from cereal grains without substantial alteration in the natural conformation of the grain berries and their retained nutritive bran coat laminations and germ elements, which consists of agitating and freelyv circulating the individual grain berries in water to soften and initially loosen their outer bran coat laminations, subsequently agitating and'freely circulating the conditioned individual grain berries in water to repetitious impingement of said berries, under the sole influence of their circulatory velocities, against and along yieldable, adherescent surfaces to that degree productive of slight indentation of the individual berries in such yieldable surfaces for the development of a momentary frictional grip of said adherescent surfaces on the loosened berry material sufll- I cient to slough said loosened material away from its associated berry, and separating the detached material from the peeled berries.

4. The method of stripping previously watersoftened, non-nutritive, exterior bran coat laminations from cereal grain berries without subtween said yieldable surfaces and the loosened berry coat ,material sulcient to overcome the natural bond between the grain berries and their A loosened outer coats and thereby non-abrasively peel the loosened material from its associated berry.

'I'I-IEODORE EARLE. 

